(1)78.5+(21.5+0.75)=([78.5 ]+[21.5 ])+[0.75 ]
(A×125)×8=[A ]×([125 ]×[8 ])
(2)(8+0.8)×12.5=[ 12.5]×[8 ]×[11 ] ×[0.1 ]
(3)2+3.9÷[ [3.75 ]-(1.1-0.6) ]=3.2
(4)若a÷b=5……2,则(a×100)÷(b×100)=5……(2 )
(5)计算0.25×4.4,简算方法是:0.25×4.4=( 0.25)×(4 )×(1.1 )或0.25×4.4=0.25×(4 )+0.25×(0.4 )
望采纳O(∩_∩)O谢谢
祝你学习进步